Manufacture of sulfuric acid.



. PATENTBD JAN. 7 HEINZ @L M.v P'. CHASE. MANUPAGTURE 0F SULFURIG ACID.

APPLICATION FILED APE.3.1006.

.UNITED sTATEs PATENT orlnon NICHOLAS L. HEINZ, OI" LA SALLE, ILLINOIS, ANE MARCH lI". CHASE, OF MINERAL POINT, WISCONSIN.

MANUFACTURE OF SULFURIC ACID.

Specification of Letters Patent.

Patented Jan. 7, 1908.

Application led April 3, 1905. Serial N0. 309.580.

United States, residing at La Salle, county of Lasalle, State of Illinois, and Mineral Point, county of Iowa, State of Wisconsin, respectively, have invented certain new and useful Improvements in BIanufacture of Sulfuric Acid; and we do hereby declare tho following to be a full, clear, and exact de- Seription of the invention, such as will enable others skilled inthe art to which it appertains to make and use the same.

Our invention relates to certain new and useful improvements in the manufacture of sulfuric acid, the purpose of the invention being to so treat the burner gases, on their way to the contact vessel or vessels, as to resent them in a form peculiarly adapted 'oreatalytio action and for the subsequent absorption of their sulfuric anhydrid and, at the same time, to produce from the burner gases, in the flue system, an additional quantity of sulfuric acid which willalso serve to quired, necessary for the operation of the several towers of the plant. To this end, We combine with the ordinary contact or catalyticprocess, a preliminary treatment of the burner gases, which consists in passing them consecutively through a dust-catcher, a Glover tower, a flue system in which a portion of the gases are converted into sulfuric acid (preferably of different strengths), and a Gay-Lussac tower, before passing on to the filter, blower, heating furnace, contact vessel and absorbing tower of the contact apparatus.' As a consequence of this preliminary treatment of the burner gases, they are deprived of their dust, the sulfuricacid `mists present are converted into liquid sulfuric acid, and impurities are either thrown down in the form of solid precipitates (such as arsenic compounds), or are absorbed by the weak acid which would otherwise tend to interfere with the efficiency of the contact material. The amount of sulfuric acid producedein the flue system is so proportioned -to the amount of-sulfuric acid produced in the contact apparatus, as to realize an increased output ver unit of niter ernployed, and permits t e maintenance of the contact apparatus, during a long continued period, in a state of high efficiency..

l55 Steam and nitric acid or other nitrous Supply the quantity of absorbing acid re` compounds are admitted into the flue system, and the flue system is associated with the Glover tower and the Gay-Lussac tower, in analogy to the association of such towers with the lead chambers o f the chamber prooess of making sulfuric acid, one portion of the acid produced in the llue system being employed for diluting the acid supplied from the Gay-Lussac tower to the Glover tower,`

and another portion of the acid produced in the flue system being added to the tank which receives the acid from the absorbing tower of the contact process,` which tank supplies said absorbing tower, and (in conjunction with the Glover tower) sup lies the Gay-Lussac tower also. The ant therefore produces within itself all of) the acid necessary for carrying on the functions of the individual towers, the subdivision of the ilue system thus permitting the roduc tion in its constituent parts of acid o different strengths, a'ipropriate to the several particular uses of the plant, 4as will hereinafter more fully appear. The surplus, representing the effective or conunercial output of the ilant, goes to the storage receptacle.

In the accompanying drawings, wehave illustrated diagramunatically, the apparatus which we prefer for carrying our invention into eil'ect. However, we do not limit ourselves to this lparticular form of apparatus.

Figure 1 represents said apparatus inelevation with the omission of the coolers and their tanks,.theacid-eggs, and the several sulfuric acid conduits intermediate of the coolers, leading from tanks and acid-eggs to the towers, Fig. 2 represents a plan view, with these auxiliaries supplied.

Similar' letters of reference indicate similar parts in both views.

lteferring to the drawing, o indicates the conduit leading from the yrites or blende furnace which conveys tie burner gases therefrom.` The conduit e opens into a dustchamber A of any suitahle'type, wherein the greater part of the dust settles, and which mayv conveniently contain a niter pot or box a', as shown, arranged in convenient. proximity to the outlet pi e leading from the dust-catcher to the G over tower B. The flue system characteristic of our invention is ,indicated by the letters c, d, joined by the arched connecting pipe e. -Into these lues c, d, extend the steam inlet pipes 7L, 4, and the two flues are preferably separate from Thepi es h, g, or similar v apparent.

each other, so that each may receive its individual supply of steam, and so that the one will, not discharge its acid into the other. By this expedient, we are enabled, by varying the quantity of steam admitted into the respective fines, to obtain acid oi dil-ferent degrees of concentration therein, as desired. ipes, may likewise serve r'orthe injection o `the desired quantities ot nitric acid or other nitrous coinpound requisite for oxidizing the SO2 in' the flue-s c, d, to the extent desired.

The tine d enters the bottom of the lGia-y- Lussac tower C, and, from the Gaydiussac tower, a conduit f conveys the gases to the filter i). From the filter l), they enter the blower l, through the conduit i, and from the blower they enter the heating furnace F through the conduit le. duit Z, they enter the contactvess'el-G which contains the usual tilling ol catalytic inaterial or contact mass. From the Contact vessel G, the gases finally pass m into the absorbing tower il, wherein thc SQ., is iinally converted into sulfuric acid, which is discharged from the pipe n into the acid tank l.'

The operation of the invention will be The main portion of the dust present in the burner gases, will be deposited in the dust catcher A, and the hot gases, still containing a portion ot their dust, 'will rise through the Glover tower B, together with nitrogen compounds from the nitcr pot e', and, being exposed therein to contact with the down ctrickling linely divided nitrous vitriol, admitted vat the top ofthe tower B, will serve (by reason of the heat contained in the gases), to ile-nitrate the nitrous vitriol, or, nitroso-suliuric acid, and, at the" saine time, will heat and concentrate lthe acid. rlh-e gases will be correspondingly cooled by interchange of temperature with the cooler acid. ri`hc Glover tower receives its nitrous vitriol from the tank :r and acid-egg u, the sup ly to Athe tank a; heilig derived from the coo er z of the Gay-Lussac tower l, and from the weaker acid o1: theiiue d, the diluted mixture in the tank being so proportioned as to be of a density of about 58o Baume. From the Glover tower, the cooled gases enter the first subdivision c ot' the flue system, and are subjected therein to thc action of nitric acid, or other nitrous compounds, and to the action of steam. They are similarly treated, but with alargcr quantity of steam, in the second subdivision d oi' the lue svstem, the arched connecting pipe (I permitting the gases to pass from the 1h10 to (he llue d, but preventing admixture ol' the acids made in the two subdivisions. Il is, therefore, feasible to make acid in one ol' the subdivisions, diilerent in strength from thi` :nid inode in the other subdivision oi the ilue system'` and, in fact. the stronger acid made in the Thence, by the conby the conduit arance ilue c, instead ot bein supplied to the Glover tower, is led by t e conduit 1" to t 1e tank i, where it iningles with the acid received from and supplied to the absorbing tower H by the contact apparatus, which is maintained at a density of about 66 Baume. Acid from the tank I is supplied by the acidegg s to the absorbing tower H, referred to, and is also supplied through the conduit o, to the tank v which supplies the acid-egg tof the Gay-Lussac tower another portion of the acid supplied to said tank u bein4 derived from' the coolers w, fw', ci the G over tower B. The pro ortions of the acid thus supplied to the tan i', are so established as to make u 'a niixture'of strongaeid therein, i. e. of aci(l of a density of 66 Baume. The surplus acid from the coolers lw, w et the Glover tower, is led by the conduit p to the tank I, and the effective output of the plant, with the apparatus arranged as shown, passes oli", through the conduit j, to the storage vats -or tanks.

In the flue' system, practically all ofthe sulfuric acid mist present in the gases, is converted into liquid sulfuric acid, by the action of the steam and nit'er, and, in this way, this niist is readilT and efectually recovered in the reliininary treatment oi the gases. This 1s of great importance, from a practical standpoint, as-itis well known that the recovery of sulfuric acid mists by mere settling in a liue or lead chamber, or even by lthe most energetic wet and dry scrubbing ol the gases containing them, is a matter of the greatest difficulty. Furthermore, in this preliminary treatment, the employment of a stronger acid than one ot 60 Baume in the Gay- Lussac tower, erinits all of the nitrogen compounds to be vmuch more readily absorbed than with 60 Baume acid. 'lhis results in aniadditional saving of niter, so that the preliminary treatment. of the gas involves but an exceedingly slight. loss, it any, of niter per pound of sulfuric acid made, in the flue system. Moreover, wefiind that, as compared with the ordinary chamber pro cess, a proportionately lar er amount of" 'S0- per unit of niter, can 'e converted int o H2SG4, in the flue system,'provide il the oxidation therein is not carried too far; that is, the burner gases, as they take their exit from ics the tlues C and d, should still contain a com- Upon issuing fromthe 'filter D, the burner V:

gases carry their burden of puriied S02 through the conduit i into the blower E. From the blower, the gas passes, by .the conduit 7c, through the usual retorts of the heating furnace F, and thence, through the connection Z, into and through the contact vessel G, and linally, by the conduit minto and through the absorbing-tower H, In the absorbing tower, the sulfuric 'anhydrid made in the contact Vessel G, is absorbed by sulfuric acid of 66 Baume, supplied from the tank i, as hereinbefore explained.

By the expedient of converting a tion of the S02 into sulfuric acid in the preliminary treatment of the gases, we iind that not only is such portion produced at `a very small cost, but that the final conversion of S02 to S03 in the converter, `requires much less platinum, for the reason that the production of the sulfuric acid in the flue system by the action of the steam and nitrogen coni pounds present therein, elfectually removes the impurities which would otherwise inter fere with the efficient action of the catalyticmatei'ial. The economy of the general system is further enhanced by the fact, hereinbefore adverted to, that no outside mixing of the acid required for the operation of the plant is necessary, the acid produced at various points therein, suflicing for all of the uses contemplated.

Having thus described our invention, what we claim is 1. The method of making sulfuric acid from burner gases; which consists in treating f lthe burner gases, on their way to the Vessels containing the contact or catalytic material,

with a nitrous compound and steam, thereby i diied gases with then remaining purifyingand drying them and converting a portion of their S02 and S03 into sulfuric acid, and finally converting the remainder' of their S02` into sulfuric acid b passing the gases into contact with cata ytic material and iinally into anSO3 absorbing tower; substantially as described.

K 2. lThe method of making sulfuric acid from burner gases; which consists in treating the burner gases, on their way to the vessels containing the contact or catalytic .inateriah with a nitrous compound and steam, thereby purifying and drying them, absorbing the niter thus introduce( soas to form nitrous vit-riol, denitiating the nitrous yitriol so as to form sulfuric acid as a portion of the final product, and obtaining a second portion of the final product bypassing the purified and SO, into contact with catalytic material and tinally into an S03 absorbing tower; substantially as described.

3. The method of making sulfuric acid fromburner gases, which consists in passing said gases successively through a Glover tower, a ilue system, and a Gay-Lussac tower, and admitting into said liuc system, a quantity of a nitrous compound and steam suflicient to convert a portion only of the S02 present into sulfuric acid and to liquefy in said [lue system the sulfuric acid mists present, the amount of steam admitted-into one portion of the llue system differing from that admitted into another portion thereof, so as to roduce acids of different strengths in the sai( llue system, appropriate to the elimination of difi'ereiit impurities; substantiallyas 4. The' method of marking sulfuric acid :from burner gases, which consists in passing said gases successivelyY through a Glover tower, a flue system, and a Gay-Lussac tower, admitting Ainto said l'lue system a quantity of steam and nitric acid sufiicient to convert a portion onl)v of the S02 present into sulfuric acid and to liquei'yr in said llue sys tein the. sulfuric acid mists, and, then passing the gases still containing a considerable residue of S02 through catalytic material and an S0, absorption tower, the acid produced in a port-ion of the llue system being employed to dilute the acid supplied from thc Gay-liussac tower or the Glover tower; substantially as described.

5. The method of making sulfuric acid from burner gases, which consists in passing said gases successively Vthrough a Glover tower, a l'lue system, and a Gay-bussac tower, admitting into said llue system a quantity of steam and nitric acid sufficient to convert a portion only of the S02 present into sulfuric acid and to liquefy in said uc sys-- tem the sulfuric acid mists, and, then assing the gases still containing a eonsiderab e residue of S02 through catalytic material and an S03 absorption tower, the acid for the Gay- Lussac tower being of more than 60 Baume.

and being supplied from the product of S0,

absor tion tower diluted by 'the product of.

C. W. BLODGn'rr W. G. STARK. 

